Geroscience: Aging and Oral Health Research

Research in aging has significantly advanced; scientists are now able to identify interventions that slow the biologic aging processes (i.e., the "hallmarks of aging"), thus delaying the onset and progression of multiple diseases, including oral conditions. Presentations given during the 3-part session "Geroscience: Aging and Oral Health Research," held during the 2023 American Association for Dental, Oral, and Craniofacial Research meeting, are summarized in this publication. Speakers' topics spanned the translational research spectrum. Session 1 provided an overview of the geroscience and health span (disease-free and functional health throughout life) concepts. The common molecular mechanisms between oral cancer and aging were discussed, and research was presented that showed periodontal microflora as a potential factor in Alzheimer's disease progression. Session 2 focused on behavioral and social science aspects of aging and their oral health significance. The keynote provided evidence that loneliness and isolation can have major health effects. These social conditions, along with poor oral health, tooth loss, and cognitive decline, could potentially affect healthy eating ability and systemic health in older adults. Research could help elucidate the directions and pathways connecting these seemingly disparate conditions. Session 3 focused on the delivery of oral care in different settings and the many barriers to access care faced by older adults. Research is needed to identify and implement effective technology and strategies to improve access to dental care, including new delivery and financing mechanisms, workforce models, interprofessional provider education and practice, and use of big data from medical-dental integration of electronic health records. Research to improve the "oral health span," reduce oral health disparities, and increase health equity must be tackled at all levels from biologic pathways to social determinants of health and health policies.

Effect of canine mesenchymal stromal cells loaded with paclitaxel on growth of canine glioma and human glioblastoma cell lines

This study investigated whether canine mesenchymal stromal cells (cMSCs) are able to take up and release paclitaxel (PTX) in active form, and therefore whether they have potential as a tool for therapeutic delivery of this drug. cMSCs from bone marrow and adipose tissue were isolated, expanded and characterised phenotypically. cMSCs were loaded with PTX (cMSCs-PTX) and their capacity for release of PTX was determined by their effect on proliferation of cancer cells. cMSCs-PTX derived from bone marrow and adipose tissue were able to take up and then release active PTX. cMSCs-PTC inhibited proliferation of the canine glioma cell line J3T, and the human glioblastoma cell lines T98G and U87MG. The potential of canine cMSCs-PTX for treatment of canine gliomas should be investigated further.

Immunotherapy with an alum-adsorbed Parietaria-pollen allergoid: a 2-year, double-blind, placebo-controlled study

A double-blind, placebo-controlled study was performed in order to confirm the safety, suitability, and efficacy of an alum-adsorbed Parietaria judaica-pollen allergoid, Allergovit, for allergen-specific immunotherapy. Parietaria pollen is an important cause of pollinosis, particularly in the Mediterranean zone, where it may be encountered for up to 8-9 months of the year. It is an aggressive allergen, and the doses tolerated during immunotherapy are less than those achieved with grass pollen. This factor increases the desirability of using therapeutic preparations with minimal IgE-binding activity, such as allergoids, in order to reduce the risk of side-effects and enable patients to tolerate a higher dose of allergen, thereby increasing the chances of successful specific immunotherapy. Forty patients with rhinitis and/or asthma were allocated at random to active- or placebo-treatment groups at the beginning of the study. All patients received the active preparation during the second year of the study. Immunotherapy was well tolerated by all patients and the incidence of side-effects was low. Treatment resulted in significant reductions in specific cutaneous reactivity and increases in nasal tolerance. A progressive improvement in nasal inspiratory peak flow in association with the immunotherapy indicated a reduction in nasal inflammation. These objective assessments of efficacy endorsed the results from the patients' diary cards, which indicated significant improvements in symptoms and reductions in the use of medication. The immunologic activity of the therapeutic preparation was demonstrated by the induction of a significant specific-IgG antibody response, with increases in IgG4 during the second year of treatment. We conclude that the safety and efficacy of immunotherapy with the Parietaria allergoid make it suitable for consideration in the treatment of patients with Parietaria-pollen-induced rhinitis or asthma.

A three-year double-blind placebo-controlled study with specific oral immunotherapy to Dermatophagoides: evidence of safety and efficacy in paediatric patients

Very few double-blind trials of oral immunotherapy have been reported. The majority of these have been performed with pollen extracts and the results have often been equivocal. The major weaknesses of these studies have been the short periods of the trials, the low doses of allergen employed and inadequate evaluation of efficacy. The present study has involved a placebo-controlled double-blind trial of oral immunotherapy for three years with Dermatophagoides pteronyssinus at relatively high doses in 18 paediatric patients. Throughout the trial clinical parameters (symptom and medication scores) and immunological parameters (specific IgE, IgG1 and IgG4 levels) were monitored in order to assess the safety and efficacy of the treatment. The treatment was well tolerated by all patients and no side-effects were experienced. Clinical improvement was evident after the second year of therapy and this was confirmed by a significant reduction in conjunctival reactivity assessed by a specific conjunctival provocation test. In addition, there were significant changes in the immunological parameters with a reduction in specific IgE and increased levels of IgG4 and IgG1, results in keeping with previous studies of oral and subcutaneous immunotherapy. Although the results do not provide an explanation of the basis of successful oral immunotherapy, they clearly demonstrate the efficacy and safety of the treatment and suggest that it may be a useful and more acceptable alternative for patients than the traditional subcutaneous immunotherapy.

[Immunodiagnosis and immunotherapy of allergic forms]

The Authors outline the immunological and immunopathogenic bases of atopy, pointing out the possible mechanisms involved in the impaired control capacity on IgE synthesis (hyperreactivity of NK cells, histamine-H2 receptors interaction, adenylcyclase stimulation, etc.). The in vivo and in vitro techniques employed in the allergological diagnosis are examined, with particular reference to the more recent tests (RAST, RAST Spot Test, Histamine radioenzymatic assay, in vitro IgE spontaneous synthesis, etc.). The latest findings in the allergological immunotherapy are then surveyed, including both the antigen non specific immunotherapy and the relevant possibility of inducing a non specific suppressor mechanism of the IgE response, and the antigen specific immunotherapy, which, besides the classical (aqueous, retard) vaccines, exploits the monovalent allergenic extracts, the allergoids (formaldehyde and glutaraldehyde) and the modified allergens (urea, PEG/PVA, D-GL, polysaccharides, photooxydation).

[Use of a new radioenzymatic test in urticaria and drug allergy]

The Authors report preliminary data obtained with the histamine release test, evaluated with a radioenzymatic technique, in patients with a symptomatology highly indicative for penicillin allergy (21 cases) and in patients with urticarial forms (20 cases) or atopic dermatitis (5 cases). This technique, suitably modified, turned out very sensitive and able to detect histamine concentrations in the picogram range. The use of this test in type I immunoreactions, after Ig removal and fixation (IgE, IgG4) from basophils of atopic and normal subjects, pointed out its remarkable advantages (sensitivity, specificity, reliability) in comparison with other techniques. The results of our case-list, even if preliminary seem to be indicative for an extension of the trial to a wider number of patients both with allergies of pharmacological type and with urticarial forms or atopic dermatitis.

[Use of an immunomodulator (levamisole) in HbsAg positive patients]

The results of some clinical trials performed with levamisole on 12 HBsAg-positive subjects, including 5 patients with aggressive chronic hepatitis, (ACH) 2 patients with persistent chronic hepatitis (PCH) and 5 healthy carriers are reported. Levamisole was administered in 2.5 mg/Kg/day doses for three consecutive days. During treatment prothrombin activity normalized in ACH and PCH as well as transaminases, the latter starting from the 4th week, even though a two-fourfold increase of the starting values was observed in the first weeks of disease. HBsAg, anti-HBs titres and immunocomplexes values did not show any significant variations, but for 1 case, while some immunological parameters (E, EA rosettes) normalized in those cases showing base- values lower than the norm.